19 replies to this topic

[ac427]

I am going to rebuild a gearbox and wondered if it was worth Helicoiling the sump drain plug thread as part of the build? 

 

I am presuming the Helicoiled thread would be stronger and more durable than the original cast aluminium thread in the gearbox case.

 

Is this common practice of am i overthinking it?

Edited by ac427, 12 April 2022 - 01:01 PM.

[Gaz66]

Theres nothing worse than doing a fresh build and at the first oil change the sump plug strips so out it all comes again and another full strip down.
Happened to me so will always check the threads pre build and if they look rough in the slightest I'll get it helicoiled.

[mini13]

Yes it is!

[mini13]

also its worth looking at timeserts, as they are a solid insert more like a bush.

[Northernpower]

I wouldn't fit a helicoil for the sump plug, I'm sure there are plenty on here who haven't had a problem with them. I think they're very good for single tightening but for multiple use I always use a timesert.

[Quinlan minor]

+1 on the Time Sert.

[Gaz66]

Hmmm, Never knew of timeserts. They look the business for future use.

[ac427]

Thank you all. Apparently there are Bigserts too for when a Helicoil installation has failed and you want to get back to the original size thread.

 

Many moons ago on my first Mini, a Mini 1000, i tapped the sump drain hole in situ, to the next size up and fitted a bigger bolt. I was careful with shavings, yeah i know not good.

 

 

Perhaps it is worth going up to the next size since the sump plug washer is so loose it never sits inline with the sump plug bolt head

 

 

What is the thread size for the sump plug, i remember 16 tpi but not the actual size?

 

[EDIT]  It looks like it is 5/8" UNC which is 11 tpi

 

 

Does the washer on the "MiniSpares Gold sump plug and washer" actually fit reasonably closely or is it the traditional dick in a bucket fitment of the original sump plug and washer?

https://www.minispar...earbox/DP3.aspx

Edited by ac427, 12 April 2022 - 06:14 PM.

[Spider]

I agonise when I do it, but the past few years, I've been fitting my own home brew 'timesert', you can see what I do here;-

https://www.theminif...p-repair/page-2

 

I'm not a 'tight-wad' but the price of timeserts in these parts, I just can't stomach given what they are.

Helicoils here seem to give too much grief.

 

Regards of what method you decide to use, most need to have the thread dead square so that when the plug is done up, the back of the head of it, ends up flat against the case in order to seal.

 

[ac427]

I agonise when I do it, but the past few years, I've been fitting my own home brew 'timesert', you can see what I do here;-

https://www.theminif...p-repair/page-2
 
I'm not a 'tight-wad' but the price of timeserts in these parts, I just can't stomach given what they are.

Helicoils here seem to give too much grief.
 
Regards of what method you decide to use, most need to have the thread dead square so that when the plug is done up, the back of the head of it, ends up flat against the case in order to seal.

I don't think Time serts are much cheaper over here.

I was thinking of buying an insert and trying to make my own tool.

A Mini specialist on eBay offers the service but they are a long way away and didn't list 5/8 UNC.

Having a harder metal insert like your method has, definitely seems like the way forward.

Edited by ac427, 14 April 2022 - 12:37 PM.

[coopertaz]

never heard of these before, look good

[Gaz66]

With your steel insert Spider....
Does the magnetic sump plug magnetise the insert and thus all the crap sticks to that as well as the plug?

[Spider]

With your steel insert Spider....
Does the magnetic sump plug magnetise the insert and thus all the crap sticks to that as well as the plug?

 

There has been some concerns regarding this and no, I find it only sticks to the normal magnet.

If you are concerned, you could always do them using a stainless steel M20 bolt. Won't rust then ;)

[ac427]

These might be a cheaper alternative insert

https://www.turnlock...mloc-keenserts/

[Quinlan minor]

These might be a cheaper alternative insert

https://www.turnlock...mloc-keenserts/

I'd be a little concerned that the grooves for the drive pegs wouldn't be oil tight for a sump plug.